The aim of this study was to document variation of deciduous tooth formation and eruption. The material comprises 121 individuals of known or estimated age (using tooth length) from Spitalfields in London, and radiographs of 61 healthy living children aged 2–5 years. Other skeletal material from two medieval Scottish archaeological sites (Whithorn, N = 74; Newark Bay, N = 59) was also examined. Stages of crown and root formation as well as eruption (alveolar, midway, and occlusal levels) were assessed for each developing maxillary and mandibular tooth from radiographs or direct vision. Age of attainment for individual stages was calculated by probit analysis, and these data were also adapted for use in estimating age. The timing of crown completion was similar to previously reported studies, but apex completion times were later. Analysis of data relative to the first and second molars at the two stages D (crown complete) and F (root length ≥ crown height) allowed comparison with the Scottish material. No significant differences were observed between population groups for tooth formation or eruption. These data fill several gaps in the literature, and will be useful in assessing maturity and predicting age during early childhood. Am J Phys Anthropol, 2003. © 2003 Wiley-Liss, Inc.